public async void Delete_Clicked_Income(object sender, EventArgs e) { var handan = await DisplayAlert("確認", "削除してもよろしいでしょうか?", "OK", "キャンセル"); if (handan) { using (var db = new MyContext()) { BindingContext = this; var item = new Tra_Income(); Income income = new Income(db); income.Delete_Income(this.viewModel.Id); } Application.Current.MainPage = new MainPage(); } //await Navigation.PopModalAsync(); }